Apparatus and method for use in free-space optical communication comprising optically aligned components integrated on circuit boards

BACKGROUND OF THE INVENTION

00011. Field of the Invention

0002The present invention relates generally to optical communication, and more specifically to free-space optical communication utilizing devices formed utilizing compact transceivers.

00032. Discussion of the Related Art

0004For digital data communications, optical media offers many advantages compared to wired and RF media. Large amounts of information can be encoded into optical signals, and the optical signals are not subject to many of the interference and noise problems that adversely influence wired electrical communications and RF broadcasts. Furthermore, optical techniques are theoretically capable of encoding up to three orders of magnitude more information than can be practically encoded onto wired electrical or broadcast RF communications, thus offering the advantage of carrying much more information.

0005Fiber optics are the most prevalent type of conductors used to carry optical signals. An enormous amount of information can be transmitted over fiber optic conductors. A major disadvantage of fiber optic conductors, however, is that they must be physically installed.

0006Free-space atmospheric links have also been employed to communicate information optically. A free-space link extends in a line of sight path between the optical transmitter and the optical receiver. Free-space optical links have the advantage of not requiring a physical installation of conductors. Free-space optical links also offer the advantage of higher selectivity in eliminating sources of interference, because the optical links can be focused directly between the optical transmitters and receivers, better than RF communications, which are broadcast with far less directionality. Therefore, any adverse influences not present in this direct, line-of-sight path or link will not interfere with optical signals communicated.

0007Despite their advantages, free-space optical transceivers have heretofore comprised bulky devices having many separate components that tend to be expensive to manufacture, in part due to alignment issues.

0008It is with respect to these and other background information factors relevant to the field of optical communications that the present invention has evolved.

SUMMARY OF THE INVENTION

0009The present invention advantageously addresses the needs above as well as other needs by providing an apparatus for communicating optical signals over a free-space link. The apparatus includes a first board, a plurality of optoelectronic converter components mounted on the first board, at least one optics element optically aligned with at least one of the plurality of optoelectronic converter components and configured to pass light directly between free-space and the at least one optoelectronic converter component, and electronics coupled to the at least one optoelectronic converter component. In one embodiment, the electronics are mounted on the first board. In another embodiment, apparatus further includes a second board having the electronics mounted thereon, wherein the second board is positioned to a side of the first board opposite the at least one optics element. In one embodiment, the plurality of optoelectronic converter components are configured in an array.

0010The present invention further provides a method of optical communication that includes the steps of providing electric signals to a plurality of lasers that are mounted on a first board, generating a plurality of optical signals with the plurality of lasers in response to the electric signals, and directing the optical signals into free-space with at least one optics element optically aligned with at least one of the plurality of lasers and configured to pass light directly from the at least one lasers into free-space. In on embodiment, the step of providing electric signals includes providing electric signals to the plurality of lasers with electrical components that are mounted on the first board and electrically coupled to the plurality of lasers.

0011The present invention provides for a method of optically communicating, including the steps of receiving an optical signal from free-space with a plurality of optics elements; directing the optical signal onto a plurality of detectors that are mounted on a first board and that are optically aligned with at least one of the plurality of optics element so that the light can be passed directly from free-space to the plurality of detectors; and detecting the optical signal with the plurality of detectors to generate corresponding electrical signals. The method can additionallyin clued the step of receiving the electric signals from the plurality of detectors with electrical components that are mounted on the first board and electrically coupled to the plurality of detectors.

0012A method of making an apparatus for optical communication is further provided. The method includes forming a substantially planar structure having a plurality of optics elements; establishing a first board; identifying locations on the first board for a plurality of optoelectronic converter components so that each optoelectronic converter component is aligned with a respective one of the optics elements; and mounting the optoelectronic converter components in the identified locations.

0013A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description of the invention and accompanying drawings which set forth an illustrative embodiment in which the principles of the invention are utilized.

BRIEF DESCRIPTION OF THE DRAWINGS

0014The above and other aspects, features and advantages of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings wherein:

0015<figref idref="DRAWINGS">FIG. 1</figref> depicts a block diagram of a previously constructed device for optical communication;

0016<figref idref="DRAWINGS">FIG. 2</figref> depicts a simplified block diagram of an apparatus for optical communication;

0017<figref idref="DRAWINGS">FIG. 3</figref> depicts a cross-sectional view of a simplified block diagram of an apparatus for transmitting and/or receiving optical signals according to one embodiment of the present invention;

0018<figref idref="DRAWINGS">FIGS. 4 and 5</figref> depict simplified block diagrams of a side elevated view of a circuit board with an optical component without a housing mounted directly onto the circuit board;

0019<figref idref="DRAWINGS">FIGS. 6 and 7</figref> show simplified block diagrams of a side elevated view of a circuit board having two layers, or two circuit boards in cooperation;

0020<figref idref="DRAWINGS">FIG. 8</figref> depicts a simplified block diagram of a cross-section view of an optical communication apparatus according to one embodiment of the present invention;

0021<figref idref="DRAWINGS">FIG. 9</figref> depicts a simplified block diagram of an overhead view of an optical component array and/or matrix;

0022<figref idref="DRAWINGS">FIG. 10</figref> depicts a simplified block diagram of a planar view of an optics array or matrix <b>330</b> according to one embodiment of the present invention;

0023<figref idref="DRAWINGS">FIG. 11</figref> depicts a simplified block diagram of an elevated view of an optical communication apparatus according to one embodiment of the present invention;

0024<figref idref="DRAWINGS">FIGS. 12–15</figref> depict simplified block diagrams of elevated views of some examples of different configurations for the optical components and/or optics according to embodiments of the present invention;

0025<figref idref="DRAWINGS">FIG. 16</figref> depicts a simplified block diagram of an elevated view of an optical communication apparatus according to one embodiment of the present invention;

0026<figref idref="DRAWINGS">FIG. 17</figref> depicts a simplified block diagram of a cross-sectional view of an optical communication apparatus according to one embodiment of the present invention; and

0027<figref idref="DRAWINGS">FIG. 18</figref> depicts a simplified block diagram of a free-space optical communication network for providing communication according to one embodiment of the present invention.

0028Corresponding reference characters indicate corresponding components throughout the several views of the drawings.

DETAILED DESCRIPTION

0029The following description is not to be taken in a limiting sense, but is made merely for the purpose of describing the general principles of the invention. The scope of the invention should be determined with reference to the claims.

0030<figref idref="DRAWINGS">FIG. 1</figref> depicts a block diagram of a known device <b>120</b> for optical communication. The device includes a circuit board <b>124</b> receiving signals <b>122</b>.

0031The circuit board generates an electrical drive signal based on the received signal <b>122</b> which is used to drive a laser diode <b>130</b> or other optical device for generating optical signals. The circuit board couples with a cable or conductor <b>126</b>, typically a flexible cable. The cable couples with the laser diode <b>130</b> to carry the electrical drive signal to the laser diode to drive the diode. The laser diode generates an optical signal <b>132</b> that is directed towards a lens <b>134</b>.

0032As is typical with laser diodes, the laser diode <b>130</b> is encased in packaging and/or a housing. This requires the step of assembling the diode into the housing, which requires time and adds cost. Further, the housing must include a means for coupling the cable <b>126</b> with the diode to receive the electrical drive signal. In some embodiments, the housing must additionally include coupling to an optical conductor or fiber for communicating the optical signal from the laser diode. The housing typically includes a metal and/or plastic casing that seals the laser diode. The housing usually includes a transparent portion or window to allow the optical signal to be transmitted. The housing further gives the device bulk to allow for easier handling. Optical detectors have similar housings to encase the optical detector.

0033In this configuration, the laser diode <b>130</b> must be aligned with the lens <b>134</b> to maximize the amount of light impinging on the lens and to avoid interference with other optical signals that might be present. This alignment requires the laser diode <b>130</b> be mounted and aligned along all three axes X, Y and Z. Thus, in constructing the device <b>120</b>, a technician must mount the laser diode and must painstakingly align the diode with the lens or lenses, or the lens(es) with the diode in all three axes. This adds considerable amounts of time to the construction of the device <b>120</b> as well as considerable cost. The cost arises in both the use of encased diodes as well as time to construct, including man hours in alignment.

0034The same or a similar configuration as shown in <figref idref="DRAWINGS">FIG. 1</figref> can also be employed for receive signals, where the laser diode is replace by a optical detector. Similarly, the detector must also be encased in packaging with coupling to the cable <b>126</b> and must be mounted. Once mounted, the detector must additionally be aligned along all three axes X, Y and Z to maximize the light received by the detector from the lens <b>132</b>. Further, the lens must also be aligned along all three axes.

0035<figref idref="DRAWINGS">FIG. 2</figref> depicts a simplified block diagram of an apparatus <b>140</b> for optical communication. A laser diode <b>146</b> (and/or detector) packaged within a housing is coupled to the circuit board <b>144</b> receiving an input signal <b>142</b>. The optical signal generated by the laser diode <b>146</b> is directly feed into an optical conductor <b>150</b>, such as a fiber optic cable. The optical conductor <b>150</b> has a terminal end <b>152</b> that emits the optical signal <b>154</b> to impinge on the optics <b>156</b>, such as one or more lenses. The laser diode <b>146</b> is typically mounted to the circuit board <b>144</b> through housing and mating socket mount or soldering.

0036Embodiments of the present invention provide a compact, integrated transceiver for optical communication, and more particularly free-space optical communication. In one embodiment, the apparatus provides an integrated multi-beam module for free-space optical communication. Similarly, the apparatus provides for a compact, integrated optical communication receiver. The apparatus can additionally include one or more receivers integrated with one or more transmitters to provide an optical communication transceiver. The integrated transmitters, receivers and/or transceivers can be incorporated into substantially any optical communication system, and in particular, substantially any free-space optical communication system and/or network.

0037The present apparatus or module combines three portions into a single module to facilitate higher performance and greater efficiency than previous free-space optical communication systems. Typically, the module includes electronic circuitry, a plurality of optical components such as optoelectronic converter components, and optics and/or optics elements for the conditioning, focusing and/or forming of communication beams. For example, the electronic circuitry can be an electronic printed circuit board that includes circuitry for distributing electrical signals and the control of optoelectronic converter components. The design and manufacturing of the electronic circuitry can include surface-mount devices, “chip-on-board” configurations (e.g., where optoelectronic converter components can be formed and/or attached directly on the circuit board), flip-chip bonding, and other similar design and manufacturing techniques.

0038The optoelectronic converter components can be substantially any component providing conversion from an electronic signal to an optical signal and/or from an optical to an electronic signal including, but not limited to, laser diodes, diode detectors, vertical cavity surface emitting lasers (VCSEL) and the like. In some embodiments, the electronic circuitry and optoelectronic converter components are combined into a single functional layer. For example, the electronics can be formed through a multi-layer circuit board and the optoelectronic converter components can be formed or fixed directly on one or more of the layers of the circuit board.

0039As introduced above, the optics elements of the present invention provide for the conditioning, formation and/or focusing of optical signals. In one embodiment, the optics elements are positioned, fixed, secured and/or formed within a carrier plate. The carrier plate can be configured to secure a plurality of optics elements within a single structure to allow mounting of the plurality of optics elements relative to the optoelectronic converter components. For example, the carrier plate can include a frame (constructed of metal, plastic and other similar materials or combination of materials capable of providing structure and support) that secures and maintains a plurality of optics elements in a fixed position within the carrier plate. The carrier plate can then be mounted or secured with a circuit board such that the plurality of optics elements optically aligned with one or more optoelectronic converter components. The carrier plate can also be formed from a single continuous piece with a plurality of optics elements formed within the plate.

0040The optics elements can be substantially any optical element known for forming, focusing and/or conditioning of optical signals including, but not limited to, discrete lenses, Fresnel lenses, diffusion lenses, mirrors, telescopes, polarization elements and substantially any other or combination of other optics elements known. These optics elements condition the optical signal according to desired effects. For example, in transmitting optical signals, the optics elements can condition a beam emitted from a laser diode to a desired divergence, or in receiving optical signals, the optics elements can focus the received optical beam to impinge on a detector device.

0041<figref idref="DRAWINGS">FIG. 3</figref> depicts a cross-sectional view of a simplified block diagram of an apparatus <b>170</b> for transmitting and/or receiving optical signals <b>176</b> according to one embodiment of the present invention. In the embodiment shown, a plurality of optoelectronic converter components or optical components <b>180</b>, <b>182</b>, such as laser diodes, detectors, other optoelectronic converter components and optical components, are directly attached or coupled with or formed within the circuit board <b>174</b>. The optical components <b>180</b> typically are not encased in a housing and/or packaging. This allows each optical component to be directly integrated with the circuit board <b>174</b>. In some embodiments, the optoelectronic converter component additionally includes a substrate (e.g., a ceramic substrate) bonded with the semiconductor optoelectronic converter component before being mounted directly onto the circuit board <b>174</b>. The circuit board can directly generate and receive signals from the optical components. Any number of optical components can be mounted with the circuit board, for example an array of four components formed in a column, two arrays of six components each in rows, and an array of 64 components formed in an 8×8 matrix, are just a few examples of possible configurations.

0042The circuit board <b>174</b> can additionally be coupled with other components, circuits and/or networks <b>173</b>, such as a local area network, a PSTN and/or the Internet. Data and/or information <b>172</b> can be communicated to and from the circuit board through the network <b>173</b> directly, or through one or more intermediate components or circuit boards. Data received from the network can be optically communicated from an optical component <b>180</b> over free-space. Optical data detected by an optical component <b>180</b> can additionally be forwarded to the network. The communication between the circuit board <b>174</b> and the network can be through substantially any communication technique including electrical, optical, wireless and substantially any other technique.

0043Mounting the optical components <b>180</b> without packaging and/or housing significantly reduces the cost of the optical components as well as reduces the size of the optical components. Further, directly mounting the optical components without packaging allows a larger number of optical components to be attached in the same amount of circuit board real estate. Additionally, eliminating the packaging allows the apparatus <b>140</b> to be constructed in a smaller size than previous systems and at a reduced weight. Not only can the apparatus be constructed with a reduced depth <b>192</b> due to the direct mounting and the elimination of packaging, but both the lengths and widths (e.g., <b>194</b>) of circuits can be reduced because the optical components require less circuit board real estate. Size and weight can be significant factors in free-space optical communication where transmitters, receiver and/or transceivers are mounted onto buildings or other structures. Reduced size and weight allows for easier mounting on less structure or building real estate with reduced load on the structure or building.

0044In assembly of the apparatus <b>170</b>, the optical components <b>180</b>, <b>182</b> can be directly attached or coupled to the circuit board <b>144</b> through substantially any method including soldering, bonding, adhesive, socket mounts and substantially any other method for attaching. Typically, the optical components are formed or placed automatically on the circuit board. In some embodiments, the optical components are positioned within predefined tolerances, such as within hundreds of micrometers (μm), preferably within tens of μm, most preferably within less than 10 μm. The positioning of the optical components can be achieved through any number of techniques including mechanical positioning, and mechanical positioning utilizing optical alignment. Because the optical components <b>180</b>, <b>182</b> are precisely aligned on the circuit board <b>174</b>, subsequent lateral adjustments of the optical components is typically not necessary.

0045One or more optics elements <b>184</b> are optically aligned and optically coupled with the optical components <b>180</b>, <b>182</b>. In the embodiment shown in <figref idref="DRAWINGS">FIG. 3</figref>, each optical component <b>180</b>, <b>182</b> is optically aligned with a separate optics element <b>184</b>. However, a plurality of optical components can be optically aligned with the same optics element, for example a single large optics element can be aligned with a plurality of laser diodes <b>182</b>, as is fully describe below. The optics elements are configured to pass optical signals directly to and from the optical components. For example, the optical component can be a laser for generating an optical signal that directly impinges an optics element. The optics element conditions the optical signal and passes the optical signal into free-space. Alternatively, the optical component can be a optical signal detector (e.g., a photo diode) for detecting an optical signal that impinges on an optics element from free-space. The optics element passes and conditions (e.g., focuses) the free-space optical signal to directly impinge on the optical signal detector.

0046In one embodiment, the optics <b>184</b> are mounted or fixed within an optics mount <b>190</b>. The optics mount secures the optics together in a single unit. This eliminates the adjustment of each optics element, and reduces the adjustments needed to optimize optical alignment and optical coupling between the optical components <b>180</b>, <b>182</b> and the optics elements <b>184</b>. In one embodiment, the optics elements are formed from a single continuous piece (e.g., formed by a molding or stamping process). For example, a single plate of plastic, glass or combination of plastic and glass can incorporate a plurality optics, such as a plurality of lenses, where each optics element aligns with one or more of the optical components <b>180</b>, <b>182</b>.

0047The optical mount <b>190</b> additionally allows the optics <b>184</b> to be mounted with the circuit board <b>174</b>. The optical mount can be configured to precisely position the optics <b>184</b> at predefined distances <b>196</b> from the optical components <b>180</b> to maximize the conditioning of the optical signals <b>176</b> and the optical communication. The distance <b>196</b> is defined by the laws of optics, such as focal lengths and divergence.

0048Typically, the optics elements <b>184</b> are configured with short focal lengths, relative to previous free-space optics elements. As such, the distance <b>196</b> at which the optics elements are mounted can be relatively close to the circuit board <b>174</b> and optical components <b>180</b>, <b>182</b>. This results in a further reduction of the depth <b>197</b> of the optical communication apparatus <b>170</b>.

0049Typically, the spacing of the plurality of optical components <b>180</b>, <b>182</b> on the circuit board is such that divergence of optical signals generated by optical components does not cause interference with neighboring optical components. As one example, the optical components <b>180</b>, <b>182</b> can be bonded directly onto the circuit board <b>174</b> with a separation between components of 30 mm. It will be apparent to one skilled in the art that the spacing of the optical components can be at substantially any distance without departing from the inventive aspects of the present invention.

0050<figref idref="DRAWINGS">FIGS. 4 and 5</figref> depict simplified block diagrams of a cross-sectional view of a circuit board <b>202</b> with an optoelectronic converter component or optical component <b>204</b>, such as a laser diode or detector, without a housing mounted and/or fixed directly onto the circuit board. The circuit board includes additional components <b>206</b>, as well as electronics <b>210</b>, such as optical component controllers, drivers, receivers and the like. The electronics <b>210</b> couples with the optical component <b>204</b> to forward electrical signals to be converted to optical signals <b>212</b> through an optical transmitter (e.g., laser diode), or to receive electrical signals converted from optical signals <b>212</b> detected by an optical receiver (e.g., detector). The coupling between the optical component <b>204</b> and the electronics <b>210</b> can be through substantially any coupling including, but not limited to, a jumper coupling <b>214</b> or through a conductor <b>216</b> (as shown in <figref idref="DRAWINGS">FIG. 5</figref>) routed within the circuit board.

0051<figref idref="DRAWINGS">FIGS. 6 and 7</figref> show simplified block diagrams of a cross-sectional view of a circuit board having two layers, or two circuit boards <b>230</b> and <b>231</b> in cooperation. An optoelectronic converter component or optical component <b>232</b> is attached on the first circuit board <b>230</b>. An electronic device or electronics <b>234</b>, such as laser driver, signal detector, optical component controller and the like, is attached on the second circuit board <b>230</b>. The electronics <b>234</b> couples with the optical component through substantially any means including, but not limited to, a jumper conductor <b>235</b>, a conductor <b>236</b> routed within the circuit boards (as shown in <figref idref="DRAWINGS">FIG. 7</figref>), a through whole via or other such coupling.

0052In one embodiment, the optical communication apparatus can be constructed with three layers. <figref idref="DRAWINGS">FIG. 8</figref> depicts a simplified block diagram of a cross-section view of an optical communication apparatus <b>250</b> according to one embodiment of the present invention. A first layer <b>252</b> includes circuit components and/or electronics, including substantially any electronic device <b>254</b> and <b>256</b>, such as microchips, capacitors, resistors, power converters, laser drivers and the like.

0053The second layer <b>260</b> includes the optoelectronic converter components <b>262</b> for generating or detecting optical signals <b>264</b>. The first and second layers can be formed as a single circuit board, as described above. Alternatively, the first and second layers <b>252</b>, <b>260</b> can be formed through separate circuit boards in cooperation. The second circuit board can be posited below or to the side of the first circuit board opposite optics elements <b>272</b>. The electronics <b>256</b> couple with the optoelectronic converter components <b>262</b> for delivering electronic signals to the optoelectronic converter components to drive the generation of optical signals <b>264</b>, or receiving electrical signals from the optoelectronic converter components generated based on received optical signals <b>264</b>. In some embodiments, a single electronic device <b>256</b> can couple with a plurality of optoelectronic converter components <b>262</b>.

0054The third layer <b>270</b> includes the optics elements <b>272</b>. The optics are optically aligned and optically coupled with the optoelectronic converter components <b>262</b>. Typically, the optics <b>272</b> are formed or mounted within a single structure <b>270</b>. The optical alignment between the optoelectronic converter components <b>262</b> and optics elements <b>272</b> is greatly simplified because the positioning of the optoelectronic converter components relative to the optics elements is performed once for a plurality of optoelectronic converter components and optics elements. Previous systems required each laser and/or detector to be positioned along the X, Y and Z axes relative to an optics element. Alternatively, in the present invention the plurality of optoelectronic converter components <b>262</b> can all be adjusted once at the same time relative to the optics elements (or optics elements <b>272</b> can all be adjusted at once relative to the optoelectronic converter components).

0055The electronic devices <b>254</b>, <b>256</b>, the optoelectronic converter components <b>262</b> and the optics <b>272</b> can be assembled in a housing, frame or casing <b>280</b>. The casing provides structure for the apparatus <b>250</b> and maintains positioning of the optics <b>272</b> relative to the optoelectronic converter components <b>262</b> and/or circuit board <b>252</b>. The casing <b>280</b> additional protects the electronics <b>254</b>, <b>256</b>, optoelectronic converter components <b>262</b> and optics <b>272</b> from the environment in which the apparatus <b>250</b> is utilized. For example, the apparatus can be mounted in or on a building in an urban area and directed to aim at a second transmitter, receiver or transceiver to provide free-space optical communication.

0056Attaching the optoelectronic converter components or optical components directly onto the circuit board without packaging allows a plurality of optical components to be incorporated into a relatively small area. Substantially any number of optical components can be incorporated on a circuit board providing substantially any configuration. <figref idref="DRAWINGS">FIG. 9</figref> depicts a simplified block diagram of an overhead view of an optical component array and/or matrix <b>302</b>. A plurality of optoelectronic converter or optical components <b>304</b> are distributed across a circuit board <b>306</b>. In one embodiment, a plurality of electronics <b>310</b>, such as optical drivers for driving laser diodes, are included on the circuit board <b>302</b>. The plurality of electronics can transmit data signals to the laser diodes to drive or modulate the laser diode in the generation of optical signals. In one embodiment, the electronics <b>310</b> are summers coupled with a plurality of optical signal detectors such that the electronics receive data signals from the detectors and sum the signals. In one embodiment, each of the plurality of electronics controls a plurality of optical components. The plurality of optoelectronic converter components can be distributed on the circuit board such that the optoelectronic convert components alternate every other component between transmitting components and detector components, or some other distribution with both transmitting and detecting components.

0057In one embodiment, a central electronic device <b>312</b> activates and/or controls each of the plurality of electronics and/or electronic device <b>310</b>, and/or controls a plurality of sub-central electronics <b>316</b> which in turn each control a plurality of electronics <b>310</b>. In configuring the optical component matrix <b>302</b>, each of a plurality of optical components <b>304</b> controlled by a single electronics <b>310</b> can be distributed at equal signal distances from the electronics device. Further, each of the electronics <b>310</b> can be distributed at equal distances or signal distances from the sub-central electronic devices <b>316</b> or the central electronic device <b>312</b>, and each of the sub-electronic devices can be distributed at equal distances from the central electronic device <b>312</b>. As such, coherence of the signals to and/or from the optical components <b>304</b> is maintained to synchronize the signals with respect to data transmission and reception, ensuring the signals to and from the central electronic device <b>312</b> are received by the central electronic device and reach each of the sub-electronic device <b>316</b> (or electronics <b>310</b> if directly coupled with the central electronic device) at substantially the same time. Still further, control signals to and from the sub-central electronics are received by the sub-central electronic an reach each of the electronics <b>310</b> at substantially the same time, and the signals to and from the electronics <b>310</b> are received by the electronics and reach the optical components <b>304</b> at substantially the same time. As such, the signal distance between a central electronic device <b>312</b> and a plurality of optical components <b>304</b> for a given channel are all substantially equal.

0058Utilizing a plurality of electronics to each control a plurality of optical components allows the apparatus <b>302</b> to operate at lower current levels. Operating at lower current levels allows the present apparatus to provide increased data rates. Distributing the optical components <b>304</b> at substantially equal signal distances from the electronics <b>310</b> maintains coherence between signals to and from the optical components. Further, the signal distances between each of the electronics <b>310</b> and the central electronic device <b>312</b> are further configured to be substantially equivalent.

0059Configuring and cooperating a plurality of optical components onto a circuit board allows the optical communication apparatus to be configured to generate optical communication paths that span a relatively large diameter. This large diameter allows for the compensation of alignment fluctuations, interference (e.g., caused by objects that can obstruct portions of the communication beam such as birds) and the like. Further, the use of a plurality of optical components allows for the compensation of turbulence, scintillation, interference or drop outs, one or more optical component failures and other effects that can degrade the level of accurate communication. The optical components can be arranged to provide spatial diversity while still maintaining angular non-diversity. Further, the optical components can be distributed at sufficient distances to achieve uncorrelated communication paths. These advantageous characteristics allow the optical communication apparatus to be very effective in providing free-space optical communication.

0060Further, utilizing a plurality of transmit optical components (e.g., in a matrix <b>306</b>) allow the communication apparatus to achieve higher total beam power while complying with lower beam power safety regulations. For example, a plurality of transmitters can be set at levels that will not damage the human eye, (e.g., each beam can operate at up to 2 mW/cm²(International Electrotechnical Commission (IEC) Class 1M)) while the total beam power of the combined transmitted optical signals is great enough to ensure accurate communication. The plurality of low power beams achieves a total needed power for accurate communication with a low power density.

0061<figref idref="DRAWINGS">FIG. 10</figref> depicts a simplified block diagram of a planar view of an optics array or matrix <b>330</b> according to one embodiment of the present invention. The optics matrix cart be incorporated in an optical communication apparatus (e.g., <b>140</b>, <b>170</b>, <b>250</b>). The optics matrix <b>330</b> includes a plurality of optics elements <b>332</b> that are optically coupled and/or aligned with one or more optoelectronic converter components and/or optical components. For example, the optical matrix <b>330</b> can include a specific number of optics elements <b>332</b> such that each optic element <b>332</b> aligns with an optical component <b>304</b> of an optical component matrix <b>302</b>, shown in <figref idref="DRAWINGS">FIG. 9</figref>. The optics elements <b>332</b> can be discrete optics secured within the matrix, the matrix can be formed as a single continuous piece with the optics elements <b>332</b> formed within the continuous piece, or the matrix can be a combination of discrete optics elements and a plurality of optics elements formed in a continuous piece.

0062The optics matrix <b>330</b> can be constructed of substantially any material or combination of materials to provide the desired optical effect. For example, the optics matrix can include a plastic structure <b>334</b> with a plurality of optics elements <b>332</b>, such as a plurality of plastic lens formed within the plastic structure. Glass can additionally be formed on or bonded with the plastic structure <b>334</b> and/or lenses to provide added support and to resist fluctuations or deformations of the lenses and structure due to temperature changes. The optics matrix <b>330</b>, whether formed of a single continuous piece, discrete lenses and/or combination thereof, can be formed or assembled in an automated manner. The cooperation of the optics elements <b>332</b> within the single optics matrix <b>330</b> greatly simplifies the alignment at the same time of the all the optics with the respective plurality of optoelectronic converter components.

0063<figref idref="DRAWINGS">FIG. 11</figref> depicts a simplified block diagram of an elevated view of an optical communication apparatus <b>350</b> according to one embodiment of the present invention. The apparatus includes a circuit board <b>352</b> with a plurality of optoelectronic converter and/or optical components <b>354</b> mounted without packaging directly onto or formed within the circuit board. The optoelectronic converter components are attached to form a matrix. However, substantially any configuration can be utilized. Further, the optoelectronic converter components <b>354</b> can be components for generating optical signals <b>356</b> and/or for receiving or detecting optical signals <b>356</b>. For example, the optoelectronic converter components <b>354</b> can alternate every other component between a transmitting component and a receiving component.

0064The apparatus <b>350</b> includes a substantially planar optics and/or carrier plate <b>360</b>, such as an optics matrix (see <figref idref="DRAWINGS">FIG. 10</figref>). The optics matrix <b>360</b> includes a plurality of optics elements <b>362</b> such as lenses, filters and/or other optics elements. In the embodiment shown in <figref idref="DRAWINGS">FIG. 11</figref>, a single lens <b>362</b> is optically coupled and aligned with a single optoelectronic converter component <b>354</b> to receive an optical signal <b>356</b> from the aligned optoelectronic converter component, and/or to focus an optical signal to impinge on the optoelectronic converter component. The optics matrix <b>360</b> is mounted or secured with the circuit board <b>352</b> through supports <b>364</b> or a housing. The supports are precisely constructed to provide a separation distance <b>366</b> between the circuit board <b>352</b> and the optics matrix <b>360</b>. The distance <b>366</b> is determined according to the laws of optics, and can be defined by one or more factors including, but not limited to, focal length of the optics elements <b>362</b>, proximity of optoelectronic converter components, dimensions of the optoelectronic converter components, divergence of the beam from the optics element, and other factors. Typically, the focal lengths of the optics elements are very small relative to optics of other free-space optical communication devices. The small and/or short focal lengths allow for a small separation <b>366</b> and thus reduces the overall size of the apparatus <b>350</b>. The beam divergence transmitted through one or more of the optics elements <b>362</b> can be adjusted by adjusting the distance <b>366</b> between the optics matrix <b>360</b> and the optoelectronic converter components <b>354</b>. The supports <b>364</b> and/or housing provide precise alignment of the optics elements <b>332</b>. Further, by utilizing the optics array formed or assembled as a single unit lateral adjustments of the optics elements <b>332</b> is avoided.

0065The embodiment depicted in <figref idref="DRAWINGS">FIG. 11</figref> shows the circuit board <b>354</b> and the optics elements <b>362</b> as separate elements. However, in some embodiments, the optics are formed or fixed to the circuit board such that the circuit board includes the optoelectronic converter components as well as the optics.

0066When a plurality of the optoelectronic converter components <b>354</b> are employed to generate and transmit optical signals, a multi-beam module is achieved for optical communication, including free-space optical communication. The failure of one or more transmitters can be tolerated when multi-beam transmission is employed. Additionally, the blocking or interference of one or some of the multiple beams can also be tolerated. This results in a high reliability of the communication apparatus. The generated optical signals can be directed and/or conditioned through the optics elements over a free-space link to be received by a receiver. The generated optical signals can be configured such that one or more beams overlap at the receiver. Further, the beams can be defocused to communicate across the link.

0067In one embodiment, each optical beam generator is set to transmit at a range of wavelengths. Further, the beam generators can be set up so that different generators transmit at different wavelength ranges. This allows the present invention to reduce or avoid interferometry effects and thus improve communication reliability.

0068The configuration of the optoelectronic converter components and/or optics can be in substantially any configuration to achieve the desired communication. <figref idref="DRAWINGS">FIGS. 12–15</figref> depict simplified block diagrams of elevated views of some examples of different configurations for the optoelectronic converter components and/or optics according to embodiments of the present invention. In <figref idref="DRAWINGS">FIG. 12</figref>, an optical communication apparatus <b>380</b> is shown with a matrix or array <b>382</b> of optics. The matrix is divided into two sub-matrices <b>384</b> and <b>386</b>. Each sub-matrix can be utilized independent of the other matrix. For example, the first matrix <b>384</b> can be used to transmit a first optical signal, while the second matrix <b>386</b> is used to receive a second optical signal. Alternatively, the first matrix <b>384</b> can be used to transmit the first optical signal, while the second matrix <b>386</b> is used to transmit a third optical signal. However, the matrices can be utilized together, for example, both matrices can transmit a first signal.

0069The optical signals can be generated at substantially any power and can be conditioned to achieve a desired signal beam. For example, transmitting at 500 m where each optical signal generated through the array <b>382</b> can have a transmit power of +18 dBm with a minimum receive power of −37 dBm, the divergence can be limited to 6 mrad with an optical loss of 4 dB, with optical power budget of 51 dB, a geometric loss of 33 dB and a margin of 18 dB. Other configurations and power levels can be utilized to achieve a desired implementation.

0070<figref idref="DRAWINGS">FIG. 13</figref> shows an optical communication apparatus <b>402</b> with a matrix <b>404</b> of optics elements <b>405</b> and/or optoelectronic converter components. The matrix includes four sub-matrices <b>406</b>, <b>410</b>, <b>412</b>, <b>414</b>. Each sub-matrix can be utilized independent of the other matrices. For example, the first matrix <b>406</b> can be used to transmit a first optical signal, the second matrix <b>410</b> can be used to transmit a second optical signal, the third matrix <b>412</b> can be used to transmit a third optical signal, and the fourth matrix <b>414</b> can be used to transmit a fourth optical signal. As another example, the first matrix <b>406</b> can be used to transmit the first optical signal, the second matrix <b>410</b> can be used to transmit the second optical signal, the third matrix <b>412</b> can be used receive a third optical signal, and the fourth matrix <b>414</b> can be used to receive a fourth optical signal. Other combinations and can be used without departing from the inventive aspects of the present invention.

0071For example, the apparatus shown in <figref idref="DRAWINGS">FIG. 13</figref> can be configured to communicate at 155 Mbps, transmitting over a distance of 300 m where each optical signal generated through the array <b>402</b> can have a transmit power of +15 dBm with a minimum receive power of −37 dBm, the divergence can be limited to 6 mrad with an optical loss of 6 dB, with an optical power budget of 46 dB, a geometric loss of 31 dB and a margin of 15 dB.

0072<figref idref="DRAWINGS">FIG. 14</figref> shows an optical communication apparatus <b>420</b> with a matrix <b>422</b> of optics elements as well as a first large optic element <b>424</b> and a second large optic element <b>426</b>. In one embodiment, each optic element of the matrix <b>422</b> can be optically coupled and aligned with a single optical component, and each of the first and second optics elements are optically coupled and aligned with a plurality of optoelectronic converter components and/or optical components. Alternatively, the first and/or second large optics elements can optically couple and align with a single optical component. In one embodiment, the optics elements can be associated with separate and different signal channels that carry logically separate information encoded, for example, on different wavelengths or with different polarizations. Further, the matrix <b>422</b> can be divided into any number of sub-matrices as described above. The communication through the matrix and the two large optics can be configured in substantially any configuration. For example, the first large optic <b>424</b> can transmit a first optical signal, the second large optic <b>426</b> can transmit a second optical signal, and the matrix <b>422</b> can receive a third optical signal. Alternatively, the first large optic can receive a first optical signal, the second large optic can transmit a second optical signal, and the matrix <b>422</b> can transmit a third optical signal.

0073<figref idref="DRAWINGS">FIG. 15</figref> shows an optical communication apparatus <b>440</b> with a matrix <b>442</b> of optics elements as well as a large optic element <b>444</b>. As described above, the matrix <b>422</b> can be divided into any number of sub-matrices. The communication through the matrix and the large optic can be configured in substantially any configuration. For example, the large optic <b>444</b> can transmit a first optical signal and the matrix <b>442</b> can receive a second optical signal. Alternatively, the large optic <b>444</b> can receive a first optical signal and the matrix <b>442</b> can transmit a second optical signal. Other combinations can be used without departing from the inventive aspects of the present invention.

0074<figref idref="DRAWINGS">FIG. 16</figref> depicts a simplified block diagram of an elevated view of an optical communication apparatus <b>450</b> according to one embodiment of the present invention. The apparatus <b>450</b> includes a plurality of sub-apparatuses <b>452</b>, <b>460</b>, <b>466</b> and <b>474</b> that are stacked and/or combined. The sub-apparatuses are similar to the apparatus <b>440</b> shown in <figref idref="DRAWINGS">FIG. 15</figref>. However, any sub-apparatus or combination of sub-apparatuses can be utilized in the assembly of the communication apparatus <b>450</b>. In the embodiment shown in <figref idref="DRAWINGS">FIG. 16</figref>, each sub-apparatus includes a matrix of optics elements <b>454</b>, <b>462</b>, <b>470</b> and <b>476</b>, as well as a large optic element <b>456</b>, <b>464</b>, <b>472</b> and <b>480</b>. As described above, the matrix of optics and the large optic in each sub-apparatus can be used to transmit and/or receive optical signals. Further, each matrix can be divided into sub-matrices as described above.

0075As an example, a first signal can be transmitted by the matrices <b>454</b>, <b>462</b>, <b>470</b>, and <b>476</b> while a second signal can be received by the large optic elements <b>456</b>, <b>464</b>, <b>472</b> and <b>480</b>.

0076Again, the optical signals can be generated at substantially any power and can be conditioned to achieve a desired signal beam. For example, the apparatus <b>450</b> can transmit at 2000 m where each optical signal generated can have a transmit power of +27 dBm with a minimum receive power of −37 dBm, the divergence can be limited to 6 mrad with an optical loss of 4 dB, with optical power budget of 60 dB, a geometric loss of 34 dB and a margin of 26 dB. With this configuration, each sub-apparatuses <b>452</b>, <b>460</b>, <b>466</b> and <b>474</b> (if not each optical component and optics element) can generate communication signals providing, for example, 155 Mbps data rates and greater.

0077<figref idref="DRAWINGS">FIG. 17</figref> depicts a simplified block diagram of a cross-sectional view of an optical communication apparatus <b>502</b> according to one embodiment of the present invention. The apparatus <b>502</b> includes a plurality of small optics elements <b>504</b> that are optically coupled and aligned with at least one optoelectronic converter component and/or optical component <b>506</b>, such as a laser, detector or the like. Each optoelectronic converter component <b>506</b> is directly mounted on a first circuit board <b>510</b> to receive and/or transmit communication data through optical signals <b>508</b>. The small optics elements <b>504</b> are configured to have short focal lengths <b>512</b>, relative to optics incorporated in previous optical communication devices, and particularly previous free-space optical communication devices.

0078The apparatus <b>502</b> additionally includes a large optics element <b>514</b>. The large optic element is optically coupled with one or more optoelectronic converter components <b>516</b>. The one or more optoelectronic converter components <b>516</b> are directly mounted onto a second circuit board <b>520</b>. The second circuit board <b>520</b> can be an independent circuit board from the first circuit board <b>510</b>, or the second circuit board <b>520</b> can be a part of a single circuit board containing both the first and second circuit boards <b>510</b>, <b>520</b>, respectively. The large optic element <b>514</b> has a focal length <b>522</b> that is longer and/or larger than the short focal length <b>512</b> of the small optics <b>504</b>. The longer focal length <b>522</b> is typically similar to the focal lengths of optics elements incorporated in previous free-space optical communication devices. As such, the second circuit board <b>520</b> is offset from the first circuit board <b>510</b>, or the first and second circuit boards are assembled on a single plane and the large optic <b>514</b> is positioned out further from the circuit boards <b>510</b> and <b>520</b> than the small optics <b>504</b>. With the large optic element having the longer focal length <b>522</b>, the depth <b>524</b> of the apparatus <b>502</b> is larger than if just small optics elements <b>504</b> had been utilized.

0079The present invention can be implemented to provide free-space optical communication. Two transceivers assembled, such as those described above or other configurations where optoelectronic converter components are mounted directly onto a circuit board, can be aligned with each other on opposite sides of a free-space link. As such, optical communication can be provided between the transceivers. The transceivers can employ a plurality of small optics elements, one or more large optics and/or a combination of small and large optics elements.

0080<figref idref="DRAWINGS">FIG. 18</figref> depicts a simplified block diagram of a free-space optical communication network <b>560</b> for providing communication according to one embodiment of the present invention. A plurality of optical transceivers <b>562</b> are distributed around an area, for example distributed through a metropolitan area. The transceivers can be mounted on or within buildings <b>564</b>, towers <b>566</b> and other structures. The transceivers are configured according to one embodiment to include a plurality of optoelectronic converter devices aligned with a plurality of optics elements to generate a plurality of free-space optical signals <b>568</b>. Because the present invention provides free-space optical communication apparatuses that can have decreased weights and size relative to previous free-space optical communication devices the present apparatuses can be mounted in positions that were previously unavailable. For example, communication apparatuses can be mounted on the sides of building, on structures than cannot support excess weights and in other locations previously unavailable. Further, because the present apparatuses can have a reduced size and weight, the apparatuses can be mounted within buildings without adversely affecting views and without affecting the aesthetics of the building interior.

0081Still referring to <figref idref="DRAWINGS">FIG. 18</figref>, the transceivers <b>562</b> are optically aligned to transmit and/or receive the optical signals <b>568</b> to provide communication of data and/or information across the network. In one embodiment, the transceivers <b>562</b> can be coupled with routers <b>570</b> or other signal distribution devices within or on the builds, or coupled with (or part of) a communication network <b>572</b>. The routers <b>570</b> are show on the buildings; however, typically, the routers are located within the building or other structures. The routers <b>570</b> can supply optical or electrical data signals to the transceiver to be communicated optically over the free-space, or to receive optical or electrical signals converted by the transceiver from the received free-space optical signals. The routers <b>570</b> can route signals within the build and/or be coupled with the communication network <b>572</b>, such as a fiber optic network, a PSTN or other network.

0082The present invention provides free-space optical signal transmitters, receivers and/or transceivers with reduced dimensions over previous transmitters, receivers and transceivers. Directly incorporating the plurality of optical components onto the circuit board allows for the elimination of the packaging and fiber optic coupling or connections of previous devices. Further, smaller optics elements are employed that are secured relative to the circuit board. The optics elements are designed to have small focal lengths, reducing the distance at which the optics are fixed relative to the circuit board and optical components. This again results in the ability to further reduce the size of the transmitters, receivers and/or transceivers of the present invention.

0083The incorporation of optical components without package and fiber optic connections reduces the weight of the transmitter, receiver and/or transceiver of the present invention. Further, the use of the small optics further reduces the weight of the present invention. Still further, the reduced dimensions of the apparatus results in less material needed for the structure and to house the transmitter, receiver, and/or transceiver of the present invention, resulting in further reduced weight. Thus, the present invention provides a lighter apparatus for optical communication.

0084The reduced size and weight allow the present apparatus to be mounted easier, at reduced costs, and in locations that previously were not accessible by previous systems. Still further, the reduced size translates to reduced area of a building or structure needed to mount the present apparatus as well as providing aesthetic benefits to the end-user.

0085Utilizing optical components that do not have packaging or fiber optic coupling, allows the present invention to be constructed at reduced costs over previous devices. Further, the present invention utilizes a plurality of low power optical components to achieve the desired receive power while maintaining low power density levels. The cost of low power transmitters is significantly less than higher power transmitters further reducing the cost of the present invention over previous systems delivering the same optical power at the receiver.

0086Further, the mounting of the optical components onto the circuit board can be achieved through mechanical means. As such, the present invention can be produced in volume at significantly reduced costs. Thus, the present invention can be constructed at costs less than previous systems.

0087The present invention employs a plurality of low power optical signals, distributed over an area resulting in low power density that meets eye safety regulations. Further, the use of the plurality of low power optical signals sum to provide the needed optical power at the receiver. Still further, utilizing a plurality of optical components (e.g., generating a plurality of free-space optical signals) allows the apparatus to tolerate one or more transmitter and/or receiver optical component failures, turbulence, and interference. The present invention can be constructed to have dimensions which further provide for incoherency to improve communication.

0088By utilizing a plurality of optical transmitters, the present invention is capable of utilizing reduced currents to drive the transmitters. Reduced currents allow for higher data rates because fewer electrons are being forced through the conducts. Thus the present invention achieves increased communication data rates.

0089The apparatus utilizes optical components mounted or formed directly on the circuit board eliminating the three-coordinate (X, Y and Z) adjustments of each optical component. Further, in some embodiments, the present invention employs the array of optics elements secured together which additionally eliminates the need to three-dimensionally align each optic.

0090While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims.